The carbohydrate binding site of concanavalin A (con A) is being studied with N-tri-fluoroacetylglucosamine. Fluorine-19 nuclear resonances are used to measure distances of fluorine atoms from the paramagnetic manganese ion in the transition metal site. The pH is being varied to study changes which might occur upon conversion of dimers to tetramers. Influence of calcium in the other metal ion binding site is also being investigated. Chlorine-35 nuclear magnetic resonance spectroscopy is being used to examine the metal ion coordination sites. This will be correlated with proton relaxation enhancement studies on water protons. The temperature dependence and pH dependence are being examined to elucidate the function played by the metal ions in determining the active conformation of con A. Because con A will bind many metal ions, the nature of the con A made by replacement of several different metal ions is amenable to study. These new derivatives will be compared with the more common Mn ion and Zn ion forms.